Pullers are available for pulling propellers from propeller shafts, bearing carriers from shafts, and the like. Moreover, pullers have been developed for pulling golf club heads from club shafts.
Although the art of pullers in general is well developed, the art has not yet reached its ultimate state of development, particularly in the golf club head pulling division of the art.
Modern golf club shafts are made of graphite or graphite reinforced with boron; some are fiberglass reinforced products. Typically, the distal end of a fiber shaft is axially received within the hosel of the golf club head and secured thereto by a thermoplastic adhesive means. Thus, when it is desired to change shafts, the hosel is heated to release the grip of the adhesive, and the shaft is manually pulled from the hosel.
The drawbacks of the just-described process are several. First of all, manual separation of the shaft from the hosel usually twists the shaft and destroys it since few people can pull hard on an object such as a golf club shaft without twisting it. Moreover, few people are strong enough to pull the shaft out until the adhesive has been greatly weakened by the application of a large amount of heat; as a result, the distal end of the shaft also becomes hot before the separation of shaft and hosel can be accomplished and the shaft is again ruined.
There is a need for a pulling device that generates a very strong, non-twisting pulling force when a golf club shaft is pulled from a club head so that the shaft can be pulled from the hosel at a time when the temperature of the hosel has been elevated to a temperature sufficient to release the grip of the adhesive but insufficient to adversely affect the distal end of the shaft.
The needed device does not appear in the prior art, nor does the prior art contain suggestions to those of ordinary skill in the art as to how such a device can be provided.
For example, U.S. Pat. No. 2,160,395 to Wettlauffer discloses a golf shaft puller having a nut that is constrained against travel by a washer so that rotation of the nut causes the axial displacement of a sleeve-like body onto which the nut is threaded. The threaded sleeve thus acts as a drive rod that separates the golf club head from the golf club shaft. However, no means are provided to accomplish an abrupt separation of the shaft and head in a non-twisting manner.
Other U.S. patents of interest include U.S. Pat. Nos. 1,662,465; 2,991,080; 3,334,405; 4,179,125; 4,317,986; 3,891,212; 4,462,595; 4,674,747; 4,783,893; and UK Pat. No. 2,186,195. Many of the puller devices of the prior art relate to pulling steel shafts from hosels; the problems relating to shaft twisting and overheating are not encountered when a steel shaft is being pulled.